1. Field of the Invention
The present invention concerns a process for the preparation of a spread product. The spread obtained with the invented process is particularly suitable for use on bread and shows a surprisingly high butterlikeness, although for its preparation no dairy fat is needed.
2. The Related Art
With regard to consistency, taste and mouthfeel butter is for many consumers still the benchmark product for assessing spreads of premium quality. Many attempts have been made to develop a spread which contains no or only little butterfat but which is similar to real butter with regard to taste and mouthfeel. See e.g. East German patent 225327, U.S. Pat. No. 4,20,9546, EP 96631 and EP 199398. The processes of the prior art either do not yield a product which is really satisfactory or the processes are complicated, expensive or require a substantial amount of butter fat (melanges).
It is known that a process for the preparation of a spread which resembles butter with respect to consistency and mouthfeel preferably should include quiescent conditions for crystallisation of the structuring fat in the fat phase. The crystallisation process should not be disturbed by any kind of working. Under such circumstances the fat crystals network obtains its highest stability which results in a maximum structured fat phase. Such post-inversion quiescent crystallisation requires, however, process conditions which seem to be contradictory.
At inversion the water continuous emulsion, containing at least 50 wt. % of fat, has to be cool, with a temperature below the melting temperature of the structuring fat. When manufacturing on an industrial scale, cooling an emulsion in a quick pace needs stirring, which inevitably causes considerable shear and working. After inversion this working is undesired and before inversion the shear contributes to crystallisation of the dispersed fat droplets, consequently resulting in a cooled and ripened cream with an undesirably high viscosity. The more or less crystallized fat globules are desired because they enhance the eventual butterlikeness perception, but their structure will be adversely affected by the high shear forces occurring in the inversion unit. Moreover, in order to have coalesced the liquid part of the dispersed fat droplets, shear forces of the invertor are used. The needed energy, however, is proportionate to the viscosity of the ripened cream, which viscosity increases when fat crystallisation proceeds. A small amount of crystallized fat is desired, however, for stabilizing the dispersed aqueous phase droplets which result from the inversion process.
The spread manufacturing process described in EP 293980 is characterised by the initial preparation of a crude emulsion. A pasteurised cream is cooled in a static heat exchanger, particularly in a tubular heat exchanger where working effects on the emulsion are largely absent. The average size of the fat droplets is at least 10 xcexcm and preferably more. Its water-continuous condition is maintained until the cream enters a working unit where the cream is inverted to a fat continuous spread. The risk of premature inversion is averted by increasing the viscosity of the water phase. This viscosity is increased by incorporating a gelling or thickening agent and, optionally, by lowering the temperature. When lowering the temperature the fat phase already starts to crystallise.
A cream with a viscous water phase requires an inversion unit with a high energy output. But, as said before, it is not desired to expose the emulsion to such high energy. The obtained spread may exhibit good quality, but no butterlikeness has been reported.
The process described in EP 199398, aims at the preparation of a spread which is fat continuous and which has butterlike properties. The initial water continuous emulsion, the cream, is conducted through an inversion unit. Premature inversion is prevented applying either of two options: keeping the cream until inversion at a safe ambient temperature, where cooling is applied only during the subsequent inversion step or allowing the cream to ripen at a low temperature so that stabilizing fat crystals have been formed before the cream enters the inversion unit. For inversion a so-called cavity transfer mixer (CTM) is used. The first option requires, however, a considerable cooling capacity of the inversion unit. When only using small volumes as described in the patent examples a process using a cavity transfer mixer may be feasible. But, since such CTM has a much limited cooling capacity and can not cope with the heat removal of large volumes, the described process will fail when it has to be carried out on an industrial scale. The second option which comprises inversion of a cooled and ripened emulsion is not suitable either, because the amount of solid fat formed before inversion is undesirably high.
None of the prior art processes is able to realize a quick inversion of a cream consisting of substantially liquid fat and resulting into a spread with a highly structured fat phase.
For the preparation of an edible butterlike spread consisting of an edible W/O emulsion which contains 50-85 wt. % of triglyceride fat, comprising the steps of
a. preparing a cream, 15-50 wt. % of which consists of an aqueous phase in which 50-85 wt. % of liquefied fat is dispersed as fine droplets,
b. pasteurizing the cream,
c. cooling the cream and then conducting it through an inversion unit where inversion to a fat continuous emulsion takes place,
d. allowing the inverted fat-continuous emulsion to crystallize to a spread, characterized in that the cream is subjected to such cooling regime that the dispersed fat, when the cream enters the inversion unit, is in a substantially liquid, supercooled condition, which condition is so unstable, that inversion of the cream is completed within 30 seconds after it has entered the inversion unit.
The present invention provides a simple, cheap and reliable process which delivers a spread which shows a surprisingly high butterlikeness and which process can dispense with the use of butter fat as an ingredient of the fat phase.